EPC Light

[P_G]

OK, so did an independent diagnostic rather than Audi as they wanted £120 for the pleasure and no fault codes came up with engine off and looking through the logs. Switched engine on and went to different section of data retrievalon emmission and found the following;

intermittent fault code 7 times

Fault Code P2020 in OBD, unknown code

Can the VAG-COM techies on here tell me what P2020 is please? I suspect something to do with O2 / Lambda or throttle body? Sure enough went on again during warm up sup 7k rpm phase. Switched off, switched on for diagnostic; switched off and when started and driven again EPC light went off.

[S2tuner]

It seems to mean something to do with one of the primary lambdas heating circuit, but I can't find much at all about this specific code...

[P_G]

So that would be consistent with the fact that it only comes on when in engine warm up phase and also the rev limiter safe mode when it is on; almost as though the sensor transmits that the cats are not warmed enough to handle increased emissions beyond 7000rpm

[S2tuner]

Not really, it's only the circuit that warms up the lambda sensor, not much to do with the cats as it's the sensor that sits before the cat in the exhaust stream. How many miles do you have on your car?

[P_G]

63500.

I was also getting my sensors mixed up, I see what you mean. Can you just replace the heating circuit?

[pad125]

Just an update, had the car in yesterday and they say the fault was 'running rich'. I'm nowhere near qualified to argue the relevance of the fuel I used (95/98RON) but it does sound a little odd. They've reset the system and I have to take it back if the light comes on again.

[S2tuner]

P_G: unfortunately the heating circuit is part of the sensor itself, so you can only change the sensor as a whole... pad125: 95/98 doesn't have much to do with rich running, see if the code comes back... Rich codes on normally aspirated cars aren't that common, whereas on turbos they're quite common as they're almost always a manifestation of a boost leak, which a B7 RS4 can't have obviously

[P_G]

The Power of the internet is a marvellous thing. This may not be right but found this list of VAG-COM fault codes http://www.gerritspeek.nl/vag-com_foutcodeslijst-i.html and apparently on this list P2020 is;

Intake Manifold Runner Position Sensor / Switch, Circuit Range / Performance Bank 2

So what difference would that make if it is faulty? Apart from the EPC light going on and restricting revs. What is this sensor's function?

Not saying this chart is right but it is an option rather then lambdas Also it seems that P2020 is a universal code for intake manifold air actuator position sensor / switch which could be wiring fault or mechanical fault related with the sensor / switch.

Those in the know, any easy fault to rectify? Like sad the EPC light is still intermittent, drove 76 of my 80 mile commute today and nothing then in the last 5 miles came on. That's the first time I've seen it since I had the car VAG-COM'ed last Friday?

[HYFR]

all sounds very similar to my fault

and this seems a more and more common fault on this forum

the EPC will most likely come back, if I was a betting man

[P_G]

So how was yours fixed?

[HYFR]

carried out several fault finding tests to confirm secondary air system bank 1 flow too low and manifold flap position sender 2 has implausible signak........replaced both manifold flap senders and air control valve

[P_G]

Do you know if you had the same fault code, sounds like you had three separate codes wheras mine appears to be one and one only.

[P_G]

Got this off of telematika.gr

P2020 Intake Manifold Runner Position Sensor/Switch Circuit Range/Performance (Bank 2)

So the explantion of the code is pretty consistent.

[P_G]

Car is going in next Thursday to a Audi Independent in Newcastle to see if they can reset the sensor. Will see what happens then; in the meantime sure enough the EPC light has gone out again.

[silverRS4]

The manifold runner position sensors monitor the tumble flap position (these are the only moving parts on the manifold - besides the throttle plate of course). The command to the tumble flaps is either ON or OFF, which essentially is TUMBLE POSITION (half open) or COMPLETELY OPEN. The normal position of the flaps is ON. This requires no vacuum. To OPEN the flaps, the master ECM sends a signal to the Intake Manifold Runner Control (IMRC) Valve, which is an electrically-switched vacuum solenoid. The vacuum circuit then energizes the Intake Manifold Flaps Vacuum Units - there are 2 - one for each engine bank, which transmit the vacuum force to lever arms attached to the flap shafts, causing the shafts to rotate. The sensors simply verify that the shafts are rotating fully to the ON or OFF position. A fault would indicate 1) a faulty sensor or 2) a sticking shaft or 3) a failing vacuum unit or 4) a vacuum leak. The "sticking shaft" cause seems to be the most common.